A toxin is a poison made by living cells or organisms. Toxins can cause health problems on contact or when they are absorbed by the body.

The severity of a reaction to a toxin varies greatly. A bee sting causes a minor reaction in most people. But eating food containing botulinum toxin can cause a deadly reaction. Usually, the severity of the health problem caused by a toxin depends on:

• How often a person is exposed to the toxin.
• How much toxin was in contact with or absorbed by the body.
• How poisonous the toxin is.

Treatment can be as simple as staying away from the toxin and limiting future exposure. In some cases, treatment with substances, such as anti-venom, can prevent serious illness.

Fortunately, the levels of most toxins in the environment are low.